Method of cleaning feed water heaters



Patented Apr. 28, 1936 PATENT OFFICE METHOD OF CLEANING FEED WATER HEA TER-S Frank H. Graham and Vern D. Washburn, Jackson, Mich.

' No Drawing. Application March 14, 1934, Serial No. 715,472

2 Claims.

The present invention relates to improvements in decarbonizing and degreasing compositions and the method of using the same and relates to our copending application, Serial No. 605,349, filed April 14, 1932.

As in our prior application the invention, although having application in all fields in which the removal of carbon, greases, oil and similar foreign matters from surfaces, is desired, is particularly concerned with the removal of the sticky, gummy carbon which accumulates in locomotive feed water heaters as a result of the oil carried in the exhaust steam employed to heat the feed water.

Likewise, as in our prior application, it is the purpose of the invention to provide a decarbonizing and degreasing composition which has a relatively high flash point, which does not evaporate rapidly, which possesses greater affinity for dissolving carbonized oils and greases than more volatile solvents for oils and greases in present use, and which may be used in an open vat within the shop without being injurious to the workman or constituting a fire hazard.

As set forth in our copending application, it was considered essential to employ a certain amount of coal oil together with the parafiin oil in order to obtain satisfactory decarbonizing and degreasing action. We have discovered, however, that equally satisfactory results may be obtained through the use of paraffin oil alone or as constituting the base of the composition. The paraffin oil employed in our process, and as known in the trade, is defined as the oil distilled off between gas oil and red engine oil. As in the case of the oil employed in our copending application, any oils distilled off between gas oil and red engine oil are found suitable to varying degrees. Such oils have a Saybolt viscosity at 100 F. of to 200 and a fiash point of 265 F. to 410 F. Preferably we employ an oil distilled off in this range having a fiash point of approximately 330 F. and of a viscosity of to at F. In the various tests that have been conducted it is found that both red engine oil and gas oil give fairly acceptable results but do not compare favorably with the oils distilled off between red engine oil and gas oil. The gas oil, although having greater cleaning properties than the red engine oil, has a lower flash point which is undesirable. The red engine oil, on the other hand, although having a, higher flash point than the paraffin oil, has inferior cleaning properties when compared with either the gas oil or the paraffin oil. It is our theory, at the present time, that this is attributable to the higher viscosity.

It is our conclusion that oils distilled off in the relatively narrow range between gas oil and red engine oil constitute the only oils which possess the desired cleaning properties for decarbonizing and degreasing surfaces of the type described, and that only such oils are capable of satisfactorily accomplishing the object heretofore set forth.

The process employed in the present invention is very similar to that disclosed in our copending application. Although it has been found that the cleaning composition of paraffin oil may be employed with a limited amount of success at atmospheric temperature and without agitation, we prefer to heat the same in a vat between F. and 300 F. and it has been found that best results have been obtained when the temperature of the oil was maintained between 250 F. and 300 F. With the temperature of the vat within the range designated the carbon and grease will be dissolved and removed from the feed water heater, and the like, immersed in the same, without agitation other than that which is set up during the removal of the feed water heater from the vat. Preferably, however, to facilitate the degreasing and decarbonizing action the vat is equipped with some suitable agitator and the liquid kept in motion about the surface of the feed water heater to be cleaned throughout the period in which the feed water heater is immersed within the vat. In this way the carbon and grease, loosened and dissolved, is removed from the surface throughout the process and the time required to completely degrease and decarbonize the feed water heater is materially reduced.

In operation, locomotive feed water heaters removed after months of service, so completely clogged with gummy carbonized oils and greases as to lower the efiiciency of the same to a point far below economical operation, have been completely cleaned by immersion from 30 to 60 minutes in a vat containing no other ingredient than paraiiin oil distilled off within the range designated. Prolonged use, without replenishing or renewing the vat with parafiin oil over which time large numbers of feed water heaters have been cleaned, has not resulted in any observable decrease in the effective cleaning properties of {the cleaning composition. The percentage of evaporation over a period of several weeks of operation was found to be less than five per cent. Although the original cost of parafiin oil is greater, in some cases, than other cleaning compositions, which were formerly used for the cleaning of feed water heaters, because of the low rate of evaporation and the ability to be reused over an extended period without appreciable decrease in the efiectiveness, its use results in effecting economies heretofore unknown through the use of the more volatile solvents. In addition the cleaning action of the paraflin oil has been found to materially surpass that of other cleaners heretofore employed for the same, or similar purposes.

Having thus described our invention, what we claim is new and desire to protect is:

1. The process of removing the gummy coating formed by the deposit of burned and carbonized lubricating oil from exhaust steam, resulting from the high temperature of the exhaust steam in exhaust steam heated feed water heaters, and

the like, which consists in immersing the heater in parafiln oil distilled ofi immediately above gas oil having a Saybolt viscosity at 100 F. of about to 200 and a flash point of about 265 F. to 410 F., at a temperature substantially between 150 F. and 300 F.

2. The process of removing the gummy coating formed by the deposit of burned and carbonized lubricating oil from exhaust steam, resulting from the high temperature of the exhaust steam in exhaust steam heated feed water heaters, and the like, which consists in immersing the heaters in paraflin oil distilled oif immediately above gas oil having a Saybolt viscosity at F. of 50 to 200 and a flash point of 265 F. to 410 F. and agitating said oil at a temperature between F. and 300 F.

FRANK H. GRAHAM. VERN D. WASHIBU'RN. 

